Stephen Leake has released the latest version of his OpenToken software. Here’s a quote from the website:
The OpenToken package is a facility for performing token analysis and parsing within the Ada language. It is designed to provide all the functionality of a traditional lexical analyzer/parser generator, such as lex/yacc. But due to the magic of inheritance and runtime polymorphism it is implemented entirely in Ada as withed-in code. No precompilation step is required, and no messy tool-generated source code is created.
The release announcement can be read here. Reading the announcement, I get the impression that version 4.0 isn’t that far of.